Hygienic sanitary towel

ABSTRACT

A sanitary towel for absorbing body fluids composed of an absorptive hydrophilic fiber filling having a cover, the cover being composed of a liquid-impermeable composite material and having a defined liquid-permeable zone. The core of the filling material contains an insert having highly absorptive polymers therein and being covered with a liquid-permeable woven carrier material, fleece or tissue. Such towels are easy to manufacture, highly absorptive and possess good tactile properties.

The invention relates to an hygienic sanitary towel for absorbing bodyfluids from a fluid outlet of the body with an absorptive filling ofhydrophilic fiber materials and at least one cover, and the process forits manufacture.

Such hygienic sanitary towels are used in various constructions, forexample, in baby hygiene as diapers or panties, in menstruation hygieneas sanitary napkins or as panty inserts and in medical practice as adressing for absorbing the exudation of a wound or as a urinal sanitarytowel. It is very important that these hygienic sanitary towels arecomfortable to wear, agreeable to the skin, not too bulky and, as far aspossible, do not develop odors. Since these sanitary towels are adisposable item, which is used relatively frequently, price anddestructibility also play a role.

The user is frequently forced to wear such sanitary towels day and nightfor several days (sanitary napkins) or even over a long period of time(diapers, panty inserts, urinal sanitary towels). The use of hygienicsanitary towels therefore frequently leads to considerable discomfort,such as skin irritations, odor development or soiling of underwear andclothing. Moreover, users frequently feel inhibited or under apsychological stress as a result of the fact that people around thembecome aware of the use of the hygienic sanitary towels, for example, asa result of the fact that the sanitary towel is so bulky that it isvisible through clothing or because the wearing of light clothing,especially of swimsuits, becomes impossible. On warm summer days, sweatfrequently develops in the area of the sanitary towels and this can bevery troublesome. Anxiety states may simply give rise to the notion thatthe sanitary towel no longer reliable absorbs the body fluid and thatthere may be seepage, which will be visible to everyone.

All in all, in spite of the considerable progress in the design ofhygienic sanitary towels, which has been achieved in the past, acomprehensively satisfactory result has not yet been achieved. Such aresult would presuppose that a product fulfils the followingrequirements optimally and simultaneously:

(a) reliable prevention of seepage;

(b) no significant, detectable odor formation;

(c) pleasant wearing, no skin irritations;

(d) small volume and therefore invisible, even when worn with lightclothing;

(e) economic to manufacture and therefore reasonably priced.

In the past, attempts to fulfil the preceding requirements for asanitary towel in numerous cases have led, in respect to requirement(a), to products of voluminous design, which have adequate absorbency,but which fulfil neither requirement (d) nor requirement (e).

Plastic film has also slready been used on the side of the sanitarytowel away from the body, in order to prevent seepage. By these meanshowever, the requirements for pleasant wearability and small volume (band c) are not fulfilled and contact of the fluid with the skin is in noway precluded. This results from the fact that when plastic film ispositioned around the outside of the cover, seepage cannot reliably beprevented in the case of, for example, sanitary napkins or diapers,because the position of the hygienic sanitary towel between the thighsadjusts to anatomical conditions and, accordingly, the edges of thesanitary towel come more or less into contact with underwear andclothing. This contact is reinforced by walking or kicking motions, sothat, accordingly, the plastic film may slip to one side and fluid maybe squeezed out. In addition, plastic films, positioned on the outsideof the covering, frequently produce undesirable rustling effects.

In order to prevent contact of the fluid with the skin or clothing,hygienic sanitary towels have been produced with a hydrophobic cover.However, this measure brings little success, because hydrophobic coversdo not provide a liquid-tight sanitary towel and because the fluids,which are stored initially, are squeezed out almost unimpededly by themovements of the body. The hydrophobic cover is merely able to achievethat fluid is not absorbed in wick-like fashion around the externalcircumference of the sanitary towel, as it is in the case of hydrophiliccovers.

It is an object of the invention to provide a hygienic sanitary towel ofthe aforementioned type, which fulfils simultaneously and optimally thepreviously mentioned main requirements (a) to (e), which is easilyhandled in use as well as when positioning is or fixing it on the body,and which is easy and inexpensive to manufacture.

This objective is accomplished inventively by the fact that the outercover consists of a liquid-impermeable composite material, has a definedliquid-permeable absorption zone on the side facing the fluid outletand, in the core of the filling, contains an insert in which there arehighly absorptive polymers.

That the new hygienic sanitary towel fulfils the set objectives in suchan outstanding manner and meets all the requirements, is conditional onthe combination of all the characteristics. The defined absorption zonein the region of the fluid opening of the body permits the fluidproduced to enter exactly there, where it should be absorbed rapidly andcompletely. This concerted absorption is also supported by the insert ofhighly absorptive materials, which develops an absorbing and wickingeffect throughout the absorptive zone and provides for a retention ofthe fluid within the interior of the hygienic sanitary towel. Thefluid-impermeable cover, in the form of the composite material in thewhole of the remaining region of the hygienic sanitary towel, on theother hand prevents the re-emergence of the fluid in the case ofprolonged use and violent movements. From the point of view of theindividual requirements, it turns out that:

The inventive hygienic towel first of all offers safety against seepage(requirement a). This is achieved owing to the fact that the sanitarytowel, because of the fluid-impermeable finish of the cover and becauseof the highly absorbent insert, holds the body fluids in the speciallycreated, relatively small, defined absorption zones as in a kind ofmoisture vault, without releasing them to the parts of the skin orclothing in contact with the sanitary towel.

The formation of odor (requirement b) is largely prevented in the newsanitary towel by the moisture-tight and odor-tight sealing of theabsorbed fluids in the interior of the hygienic towel.

The new hygienic towel furthermore is pleasant to wear and represents nodanger of irritating the skin (requirement c). By the extensiveshielding of skin and underwear from contact with the fluid, skinirritations are prevented. The pleasant, soft nature of the carriermaterial of the outer cover is fully retained even in the compositematerial, because the impermeable layer is positioned at the inner sideof the sanitary towel.

The sanitary towel moreover is small and can be worn even with lightclothing (requirement d). Because the highly absorbent insert in thecore of the sanitary towel is utilized to a high percentage, thesanitary towel can be made thinner and smaller than before, withoutrunning the risk of saturating it.

At the same time, the special construction and arrangement of theinsert, according to the further development of the invention, plays asignificant role. The insert preferably consists of tissue paper, whichhas been folded once or several times and on which, before the folding,highly absorptive polymers are applied in granular or fiber form. Thesehighly absorptive polymers are well known as such. They are capable ofabsorbing one hundred times their weight of liquid, without increasingtheir volume. For this purpose, two groups of materials particularlycome into consideration, namely crosslinked carboxymethyl celluloses andpolyacrylates. The latter are particularly preferred because they haveoutstanding absorptivity, even for blood. The highly absorptive polymersare preferably applied on an equally well absorbing material, for whichcotton and tissue tape, which is especially preferred, come intoconsideration. This is a very good absorbent and therefore develops awicking action and readily transmits the fluid, which is to be absorbed,to the highly absorptive polymers. The highly absorptive polymers areadvisably enclosed in and retained by the tissue paper by repeatedlyfolding this paper.

It is particularly advantageous to provide the suitable tissue tape,which is preferred as a carrier material for the highly absorptivepolymers, with a waffle pattern on a calendar in order to create a largenumber of small pockets in which the highly absorptive polymer,particularly when it is used as a granulate, is accommodated. Thisembossing of the tissue tape can take place before the highly absorptivepolymers are applied. However, the procedure is preferred in which thehighly absorptive polymers are applied on a tissue tape of at leasttwice the width of the insert. The free edge region is then folded over,so enclosing the highly absorptive polymers. Only then is the wafflepattern embossed by calendering. The embossing creates the pockets inwhich the highly absorptive polymer preferably accumulates and, at thesame time, bonds the two or three layers of tissue tape, obtained by thefolding process, sufficiently firmly to each other. Because the highlyabsorptive polymers, lying loosely together as fibers or as a finegranulate, do not develop any mutual capillarity, the tissue paper withits wicking action action takes over the drainage of the fluid to thestorage pockets with the highly absorptive polymers. These in turnabsorb up to one hundred times their weight of fluid without increasingtheir volume appreciably and without releasing this fluid again, noteven when subjected to squeezing.

The arrangement of this tissue tape, which contains the highlyabsorptive polymers in the core of the sanitary towel, as shown in FIGS.6, 7 and 8, guarantees that the fluid will remain in the interior of thesanitary towel and, at the same time, avoids saturation and thedevelopment of any odors and, moreover, makes a particularly thin andsmall construction of the hygienic sanitary towel possible.

Finally, the hygienic sanitary towel is economic to manufacture andtherefore inexpensive (requirement e). Because of the small size and thecorrespondingly small amount of material used, as well as because of thespecial construction of the internal cover, an economic manufacture oncommercially available machines is possible. The new sanitary towel cantherefore be offered very inexpensively.

The composite material, which forms the outer cover, preferably has thefollowing construction. On the outside, it consists of aliquid-permeable carrier material of a woven fabric, fleece or tissueand therefore is decidedly skin compatible and comfortable to wear. Withthe exception of the defined absorption zone, it consists on the insideof a liquid-impermeable layer, which prevents passage of the fluid tothe outside. At the same time, it is very important that the carriermaterial and the liquid impermeable layer are combined into a compositematerial, that is, that they do not lie loosely together as before,optionally bonded at the edge zones of the hygienic towel. Time andagain, with the unavoidable movement of the body, this leads toemergence of the fluid between the layers and to a squeezing out of thefluid.

Preferably, the carrier material is also made hydrophobic because, inthe region of the defined absorption zone, it comes into direct contactwith the fluid, which it should not absorb. In this connection,hydrophobic merely means that it absorbs no or only a little fluid. Inspite of its hydrophobic finish, the carrier material allows the liquid,which is to be absorbed, to pass through under body contact and to beabsorbed by the filling.

The inner, liquid-impermeable layer of the outer cover, that is, of thecomposite material, is preferably produced by laminating, calendering,extruding, coating, bonding or one-sided impregnating, printing orscattering. In this connection, bonding is understood to be theapplication of a binding agent, for example, in the form of a plastic,or of a rubber latex. In the case of one-sided impregnation, the carriermaterial is allowed to contact the impregnating liquid only at thesurface of the impregnating bath, so that the impregnation is notthorough. Because of its simplicity and speed, the application of theliquid-impermeable layer by printing is especially preferred.

Materially, the liquid-impermeable layer preferably consists of plasticfilm, thermoplastic powders, thermoplastic pastes, hot or cold-settingadhesives, polyurethane, rubber, chemical bonding agents, impregnatingagents or polyvinyl alcohol polymers of time-limited water stability,such as are produced from polyvinyl acetates by a quite specific degreeof saponification. The time-limited water stability, which is achievedhereby, enables the hygienic sanitary towels, so finished, to be flushedaway with much water, that is, they can be flushed away in a toilet.

Colored coatings, impregnations or bondings and printings have alsoproven their value, because they clearly delineate the impermeableregions from the permeable regions of the cover. The colored developmentof the liquid-impermeable layer has the advantage that embossings, suchas, for example, trade marks, can also be applied.

In the case of the hygienic sanitary towel for absorbing body fluid,special importance is attached to the defined absorption zone and itsrefinement. Inventively, a type of window, the so-called absorptionzone, is left blank in the outer cover of the liquid-impermeable,composite material, as a result of the fact that this region is leftblank by the liquid-impermeable coating, and fluid can accordinglypenetrate there. This liquid-permeable absorption zone can have a shapewhich matches the fluid outlet opening, which it is to cover. In certaincircumstances however, the liquid, which is to be absorbed, can beprevented more reliably from seeping or running past by providing theabsorption zone with absorption arms extending in all directions. Inorder to improve the drainage and to pass on the fluid to the highlyabsorptive insert, the adsorption zone itself may be perforated orneedled.

The insert of the inventive hygienic sanitary towel consists in theinterior of the filling, preferably of a tissue tape, which has beenfolded once or several times and on which the highly absorptive polymersare applied before folding in fiber form or in the preferred granulateform.

In so doing, a form of construction for the insert is especiallypreferred, in which a waffle patter is embossed in the singly orrepeatedly folded tissue tape with a calender, so that the highlyabsorptive polymers in granulate form are stored in numerous smallpockets and therefore are fixed very uniformly and immovably over thewhole length and width of the insert. This introduction of the wafflepatter can take place already before the addition of the highlyabsorptive polymers. Preferably however, the highly absorptive polymersare previously applied to the tissue tape, which is then folded once andpreferably twice. Only then is the waffle pattern embossed bycalendering. This has the advantage that the granulate collects in thepockets so formed and that, at the same time, the layers are bonded toeach other.

It is however also possible and entirely advisable to anchor the highlyabsorptive polymers additionally on the tissue tape, for example, withan adhesive or by a careful wet treatment of the tissue tape. The amountof liquid, required for this purpose, is extremely small in comparisonto the large amounts of liquid, which the highly absorptive polymers arecapable of absorbing, so that their efficiency is not impaired to anappreciable extent by such a wet treatment.

That the highly adsorptive polymers preferably are applied on a tissuetape is justified by the fact that tissue has an outstandingdistribution action for liquids and develops a large wicking effect andso carries the fluid in an outstanding manner to the highly absorptivepolymeric materials.

The particular advantage of this inventive refinement of the hygienicsanitary towel, especially of the exterior cover and the insert,consists moreover of the extreme economic efficiency of processing andmanufacture. All previously known processes and machines formanufacturing hygienic sanitary towels process all components of thesanitary towel in one processing step on the machine. In particular, thevarious layers of the cover of the filling are supplied by rolls andmust be arranged by accurately positioning them, turning them in,overlapping and gluing them, etc. around the hygienic sanitary towel. Inso doing, the covering material, which has a relatively high surfacesmoothness, tends to slip aside. It is moreover obvious that the moreindividual components of a hygienic sanitary towel must be combined onone machine, the more complicated is the guidance of the machine and themore expensive the work load represented by threading, changing rollsand warehousing.

These deficiencies are largely avoided by the inventive coveringmaterial. Owing to the fact that the outer cover is designed as acomposite material, the technical possibility exists of producing thiscomposite material in a preliminary step, completely independently ofthe actual production machine for the hygienic sanitary towels.

This preliminary step of the operating procedure can be separated interms of space and time from the later main step. Thus, in the case of apreferred process according to the most rational manufacturingtechniques, material webs are manufactured in large machine widths,which are cut up later as required according to the various widths ofthe sanitary towels. The rolls, so cut up, can now be processed furtheron the hygienic sanitary towel machine at particularly highmanufacturing speeds, because they

1. are, owing to the interlocking system, more stable than comparablematerials supplied as multiple webs. In this connection,fleece+tissue+plastic film are to be regarded as is usual. Especiallythe plastic film, which is only 15-20μ thick, is inclined to bedifficult to process owing to static charge, a smooth surface andinstability. When laminated on the carrier material, that is, as acomposite material, these difficulties are avoided.

2. permit a higher work intensity, once again owing to the use of acomposite material as outer cover and due to the smaller number of workstations, the easier manipulations, the fewer roll changes, etc.

A highly preferred process for the manufacture of an inventive hygienicsanitary towel consists therefore in that on a carrier material, whosewidth is a multiple of the width of a cover, a large number ofliquid-impermeable layers are applied so as to leave the absorptionzones bare and combined into a composite material, then divided up intothe number of individual webs corresponding to the multiple of the widthof the cover and, in a separate processing step, the cover is foldedaround the filling containing the insert and finally cut up into theindividual sanitary towels.

The particular advantage of this process lies in the fact that the widewebs of carrier material can be provided with a large number ofliquid-impermeable layers, arranged side by side, in conventional, widecoating or printing equipment and combined into a composite material,without the speed of this process being dependent on the speed of theequipment for manufacturing the hygienic sanitary towel.

A preferred process for the manufacture of the insert with the highlyabsorptive polymers consists in that on a tissue tape of at least thetwofold and preferably the threefold width of the insert, the highlyabsorptive polymers are applied across the width of the insert, the freeedge zone or zones is or are folded over and that subsequently thewaffle pattern is embossed by calendering and, afterwards, theindividual layers of the tissue tape are combined with one another.

Further details of the invention are explained by means of the schematicrepresentations of examples of the construction.

FIG. 1 shows the plan view of a hygienic sanitary towel with anabsorption zone running straight through the center;

FIG. 2 shows a cross section and plan view of the insert in the form ofa triply folded, highly absorptive tissue tape before the embossing;

FIG. 3 shows an enlargement of a section of the insert of FIG. 2 afterthe waffle pattern has been embossed by calendering;

FIGS. 4 and 5 show the manufacture of the insert by the application ofhighly absorptive polymers on a tissue tape, in side elevation and planview;

FIGS. 6 and 7 show cross sections through two different examples of theconstruction of the hygienic sanitary towel;

FIG. 8 shows a longitudinal section through the sanitary towel accordingto FIGS. 1 and 6;

FIG. 9 shows a sanitary towel in plan view with a longitudinallyarranged absorption zone with zig-zag-shaped absorption arms; and

FIG. 10 shows a sanitary towel in plan view with an absorption zone withabsorption arms arranged in star-shape fashion;

FIG. 11 shows a cross section and plan view of composite material of theouter cover;

FIG. 12 shows the process for the manufacture of the composite materialfor the outer cover;

FIG. 13 shows a cross section through the composite material;

FIG. 14 shows the process for the manufacture of the hygienic sanitarytowel.

The drawings of FIG. 1 shows a hygienic sanitary towel in plan view witha straight absorption zone 1 running parallel to the longitudinaldirection of the hygienic sanitary towel, liquid-impermeable regions 2arranged on either side of the absorption zone 1 and closure zones 3provided at the longitudinal ends.

FIG. 2 shows a cross section through the insert 10 of a highlyabsorptive tissue tape 8, in which the tissue tape 8 is folded twice sothat the highly absorptive polymers 9 have a double cover of tissue onone side. The insert 10 has not yet been embossed and consolidated bycalendering here.

FIG. 3 shows the enlarged plan view of insert 10 with representation ofthe waffle pattern, the combination of the three layers of tissuebrought about by the waffle calender and the associated formation ofpockets.

FIGS. 4 and 5 show the process for manufacturing the insert 10 and theapplication of the highly absorptive polymers 9.

The tissue tape 8 is supplied from an unwinding mechanism 14 to ascattering and folding unit 15 and the highly absorptive polymer is fedto the tissue tape 8 by means of a feeding screw 16. In the foldingequipment 17, a third of the width of the web of the tissue tape 8 isthen folded from the right and from the left over the middle third, sothat the width of the insert 10 now results. This folded insert tape isnow passed through the calender rollers 19, 20, of which the upper isthe hard-steel roll 19, which embosses the waffle pattern, and the lowerthe soft calender roll 20. Insert 10, whose individual layers are bondedby calendering and embossing, is finally taken up on the take-upequipment 18 as an endless tape.

FIG. 6 shows a cross section through a hygienic sanitary towel accordingto FIG. 1. The absorption zone 1 here lies on the underside of thehygienic sanitary towel in the region in which the liquid-impermeablecoating 6, which is provided on the inner side of the carrier materialof the external cover 5, is discontinuous. The cover 5 is filledessentially with a filling 7 of hydrophilic fiber material, mainlycellulose fluff. In the core of filling 7, there is the insert 10, whichconsists of the tissue tape 8, which has been provided with the highlyabsorptive polymers 9. A glued seam, which is formed from an adhesive11, for example, a hot melt, and a silicone paper 12, is provided on theside of the hygienic sanitary towel which lies opposite to theabsorption zone 1.

The hygienic sanitary towel according to FIG. 7 is constructed quitesimilarly to that of FIG. 7. The essential difference consists of thefact that the filling 7 of cellulose fluff is enveloped once again in anenveloping tissue paper 21.

FIG. 8 shows the longitudinal section through a sanitary towel accordingto FIGS. 1 and 6, and moreover through the center of the hygienicsanitary towel, that is, through the region in which the definedabsorption is left free from the coating 6. The tissue tape 8 is foldedonly once here around the layer with the highly absorptive polymers 9.At the same time, essentially the reference numbers of FIG. 4 have beenused.

The hygienic sanitary towel according to FIG. 9 differs from that ofFIG. 1 especially due to the fact that the absorption zone 1 does notmake straight boundaries with the liquid-impermeable regions 2, butzigzag-like boundaries 13, running in the longitudinal direction.

In the case of the hygienic sanitary towel of FIG. 10, the absorptionzone 1 is located essentially centrally within a liquid-impermeableregion 2. At the same time, the absorption zone 1 may have star-shapedabsorption arms 13, which partially extend in the longitudinal directionof the hygienic sanitary towel and partially irregularly in the crossdirection similarly to the longitudinal lines of FIG. 9. For this formof construction, the printing process for applying theliquid-impermeable coating 6 on the carrier material and so creating theimpermeable regions 2, is particularly recommended.

FIG. 11 shows a cross section through the composite material of theouter cover 5 of material 4 and coating 6, as well as the plan view of asection of the composite material in the running direction, in which theabsorption zones 1 are visible.

In FIG. 12, the process for the manufacture of the composite materialfor the outer cover 5, using a sanitary napkin as an example, is shown.On a hydrophobically finished carrier material 4 of four times the widthof the outer cover 5 of an individual hygienic sanitary towel, 5 stripsof a thin polyethylene film, 15μ thick, are laminated between rollers22, the three inner strips being twice as wide at 105 mm than the twoouter strips, which are 52.5 wide. The space between the strips of film,which forms the absorption zone 1, amounts to 35.5 mm. At both edges, anedge strip 24 of 20 mm remains unlaminated and is later removed with theedge cut. By cutting up the composite material in the longitudinaldirection along the center of the wider of the applied strips of film bymeans of a longitudinal cutter 23, the wide web is then divided intofour strips of composite material, each having the width of an outercover 5, and wound up on a roll.

In FIG. 13, the longitudinal cutting up into individual webs of theouter cover 5 is indicated by dotted lines.

FIG. 14 schematically shows the process of manufacturing the hygienicsanitary towel. Insert 10 is introduced between two strips of cellulosefluff which, combined together, from the filling 7. The compositematerial is supplied from below as the outer covering 5, and moreover insuch a manner that the coating 6 faces upwards at the impermeableregions 2, that is, the carrier material lies at the bottom. The tape,consisting of filling 7 and insert 10, is cut at cutting site 26 with acutting device, which is not shown, into individual cushions 25, whichare placed consecutively, at a distance of about 2 cm, on the outercovering 5. The outer covering 5 is subsequently folded as a uniformcomposite material about the cushions 25 so that the edges, as can beseen in FIGS. 6 and 7, overlap somewhat. Ultimately, the silicone paper12 is supplied and finally cut up at the cutting site 27 into theindividual hygienic sanitary towels with simultaneous bonding byembossing of the ends of the outer covering 5, projecting front andrear.

I claim:
 1. Hygienic sanitary towel for absorbing body fluid from afluid opening of the body, consisting of an absorptive filling ofhydrophilic fiber material with at least one cover, characterized by thefact that the outer cover (5) consists of a liquid-impermeable compositematerial and has a defined liquidpermeable absorptive zone (1) at theside facing the fluid opening and contains in the core of the filling aninsert (8) in which there are highly absorptive polymers and consists onthe outside of a liquid-permeable carrier material (4) of wovenmaterial, fleece or tissue and, on the inside, with the exception of thedefined absorption zone (1), of a liquid-impermeable layer (6) andwherein insert (10) in the core consists of tissue paper, 8 which isfolded once or several times and on which the highly absorptive polymersare applied before the paper is folded.
 2. Hygienic sanitary towel forabsorbing body fluid from a fluid opening of the body, consisting of anabsorptive filling of hydrophilic fiber material with at least onecover, characterized by the fact that the outer cover (5) consists of aliquid-impermeable composite material and has a defined liquid-permeableabsorptive zone (1) at the side facing the fluid opening and contains inthe core of the filling an insert (8) in which there are highlyabsorptive polymers and consists on the outside of a liquid-permeablecarrier material (4) of woven material, fleece or tissue and, on theinside, with the exception of the defined absorption zone (1), of aliquid-impermeable layer (6) and wherein insert (10) consists of atissue tape (8) which is folded once or several times, is calenderedwith a waffle pattern and constains the highly absorptive polymers (9)stored in granulate form in a large number of small pockets.